The Rockies made the deal Monday. They also put lefty starter Tyler Anderson on the disabled list.
Colorado said Rosscup would be optioned to Triple-A Albuquerque. He was designated for assignment Thursday after making one appearance for the reigning World Series champions, getting two outs in a game May 22 against the Giants.
Carasiti had been at Triple-A. He made 19 appearances last year in the only major league time of his career, going 1-0 with a 9.19 ERA with 11 walks and 17 strikeouts. At Albuquerque this season, he was 1-1 with a 2.37 ERA in 27 outings.
